Very little money earned from missions leads to people not being able to buy the upgrades necessary to win levels. This game is unbalanced and not fun, but could be with some adjustments.
It's fun, but has flaws. For instance, instead of having a tower destroyed when its out of ammo, why not just make it inactive and allow us to reload it, or make it so the enemies can't just walk through the rubble. The cost to build a tower that is almost instantly destroyed compared to the money received from most enemies is not balanced, it's really not fun to have to level grind and seemingly not make any kind of progress.
The game is fast paced, but we get nothing for that, the upgrades are only obtained after level grinding for money and it gets repetitive fast. The enemies off screen are annoying, rebuying old guns is absurd, at least let me sell them and the perspective should be zoomed out a little bit.
Also, if there were enemies localized to the area instead of the same old tanks and ships it would be a lot better. I am playing on the sea floor and I have the same old tanks and ships coming at me.
Another thing, if I pop balls of a certain color and they end up bringing together balls of another color it should cause a chain reaction and pop. It doesn't.
This is just a bad game. I love this type of game normally, but the bubbles take far too long to pop, the new layer coming in when I shoot throws everything off, there is no indication on when or why a new layer is coming, sometimes I have a targeting line sometimes I don't and sometimes it only appears for a split second then disappears.
Fun game, but a couple suggestions. Fix the problem where I play a previous level I don't have any upgrades, sometimes people want to level grind in upgrade games. Also, I read in the description that using select level will override progress... that should be fixed also as there is no point in having a level select if it overrides the game progress and puts the player back to the earlier level.
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Fixed, I guess.